Radioreceiver



March 3, 1931. 5, WASHINGTON 1,794,936

RADIORECEIVER Original Filed Feb. 9, 1927 2 Sheets-Sheet l INVENTOR flowdem Was/kiwi? March 3, 1931. a WASHNGTON 1,794,936

' RADIORECEIVER Original Filed Feb. 9, 1927 2 Sheets-Sheet 2 JC O J 0 1g 9 A LO "I'DEZB.

FREQUENCY CONTROL OSCILLATOR Ill/[ VOL l/ME CON TR 01.

INVFRTOR Patented Mar. 3, 1931 UNITED STATES PATENT OFFICE BOWDEN WASHINGTON, OF NEW YORK, N. Y., ASSIGNOR TO REMOTROLE CORPORATION, A CORPORATION OF NEW YORK RADIOREGEIVER Original application filed February 9, 1927, Serial No. 166,992. Divided and this application filed September 6, 1927. Serial No. 217,707.

One object of my invention is to produce a remote controlled radio receiver in which the wavelength to which it best responds and the volume of the output may be controlled from a distant point without the use of connecting wires, cables or chains.

The main object is to provide apparatus for use with existing rece1vers or amplifiers to attain the above mentioned results. The modern broadcast receiver has suflicient undistorted output to be clearly heard anywhere on a single floor of the average dwelling house or anywhere in the average apartment. A receiver of this type is too large and heavy to be conveniently movable from room to room. Yet, it is most annoying for the lis- 'tener to have to remain by the receiver in order to effect a change of program, when desired, or to be continually getting up and going to the receiver to change the program or the volume. One object is to rovide a method of reception and control w ich will make it possible for the operator to enjoy such program as he desires with a minimum effort.

By means of my invention, which will not add prohibitively to the cost of the receiver,

both these adjustments may be effected from a distance. The control box may be made small and light enough to be readily portable. Its power may be supplied from the alternating current house mains or other source and it may be provided with a cord and plug so that it may be attached to any existing lamp socket, base plug or other outlet.

This ap lication is a division from my application I 0. 166,992 filed Feb. 9, 1927, in which the invention is broadly claimed.

Referring to the drawings, Fig. 1 is a sche- .matic wiring diagram of the principal parts of a receiver embodying-one form of my invention with a schematic wiring diagram of its control station.

Fig. 2 is a partly schematic and partly diagrammatic drawing of a form of my invention which may be readily associated or used with the usual tuned radio frequency receiver or other sufficiently sensitive set.

In Fig. 1 the antenna 5 is connected to the ground 6 through the primary 7 of the band hand amplifying transformer 13' constituting the input circuit of the tube 16.

The output circuit of the tube 16 is coupled by means of-the band amplifying transformer 17 to the detector tube 18 whlch may be provided with the grid leak 19 and the grid condenser 20. The output of the tube 18 includes an intermediate frequency resonant circuit frequently called a filter circuit consisting of a condenser 21 and the inductance 22. The inductance 22 forms the primary of the intermediate frequency transformer 23 having a secondary 24 included in the grid circuit of the intermediate frequency amplifying tube 25. Two additional intermediate frequency transformers 26 and 28 may be provided with their respective tubes 27 and 29. The output of the tube 29 is coupled by intermediate frequency transformer 30 to the in-put circuit of the detector tube 31. This circuit consists of the secondary inductance 32, the grid leak 33 and the grid condenser 34. Terminals 35 and 36 are provided so that the output of the detector 31 may be introduced into any suitable indicating device such as an audio frequency amplifier or head phones (not shown).

The control station 40 may be provided with power in any suitable manner, for instance at its input with a cord andplug 41 for providing alternating current power to the primary 42 of the transformer 43, the amount of power being regulated by the rheostat 44 which serves as a gaincontrol for the receiver. One secondary 45 of this transformer may have its terminals connected to the plates 46 and 47 of the full wave rectifier 48 The filament 49 of this rectifier may be heated from the winding 50 and the filament 51 of the oscillator tube 52 may be heated from winding 50'. The central point of the secondary 50 may be led through the smoothing inductance 54 and the feed back coil 55 to the anode 56 of the oscillator tube 52.

The filtering condensers 57 and 58 may be provided. The grid circuit of the oscillator may consist of the inductance 59, the radiating loop 60 and the variable condenser 61. The grid return of the oscillator may be brought to the central point of resistance 62 which is also connected to a central tap 53 of the Winding l5.

The tubes 11 and 16 with their associated circuits form a band amplifier which will amplify with substantial uniformity over a desired band of frequencies, such as, the present broadcast band (550 to 1500 kilocycles). A predetermined frequency such as 50 kilocycles may be chosen as a resonant frequency of the filter transformer 23 and as the peak frequency of the following intermediate fre quency amplifier system. The band ampli fier is provided to make up for the gain lost by not using a resonant input circult.

In operation, the remote control station is set in operation and the condenser 61 is adjusted until the energy radiated from the loop 60 into the input of the receiver differs in frequency from the wave that it is desired to receive by the predetermined frequency chosen for the resonant frequency of the super-audible intermediate frequency amplifier system, thus producing a beat frequency in the output of the tube 18 which is resonant to the intermediate frequency amplifier.

The strength of the output of the receiver may be varied by varying the strength of the oscillations radiated from the loop 60 by various means such as the rheostat 44. The

loop 60 may preferably be in a horizontal plane, thus polarizing its radiation in a manner least liable ,to affect other neighboring recelvers. v

Fig. 2 shows a method of applying my invention to ordinary tuned radio frequency types of receivers. In this case a differential frequency converter unit 80 is provided which is inserted between the antenna system 5 and the input of a receiver 82. In case theinput of the receiver 82 includes a series condenser this condenser should be shorted or a radio frequency choke placed acrossthe input terminals to allow for the direct current anode flow. The remote control box oscillator 40 such as heretofore described and shown in Fig. 1 is provided.

The converter 80 as illustrated has a twostage band amplifier and detector similar to that associated with tubes 11, 16 and 18 in Fig. 1.

In operation the tuning controls 84, 85 and 86 of the receiver 82 are adjusted in any suitable manner until their associated circuits are resonant to the same frequency,'which fre quency may preferably be the lowest at which the receiver will operate. For purposes of explanation, let us assume that this frequency be 500 kilocycles and that the frequency'band which it is desired to receive be from 1500 to. 550 kilocycles. Then, if the oscillator 40 has a ran e of 2000 to 1050 kilocycles, 500 kilocycle heats can be produced at will in which case the usual radio frequency part of the receiver 82 will function as an intermediate frequency amplifier. The detector of this set 82 will now function as a seconddetector for its audio frequency amplifier and excite the loud speaking telephone 87 or other device.

Owing to the fact that there is no resonant selectivity at the incoming signal frequency it may be found advisable to employ more than a single stage filter in the intermediate frequency circuits.

It is also advisable to choose such a resonant peak frequency for the intermediate frequency filter amplifier that beats between any two transmitting stations will not be in resonance with this amplifier. For instance, with the present interval between broadcast stations of 10 kilocycles a frequency of 40 or 50 kilocycles can be produced by stations 3 or 4 intervals apart but if 45 or 55 kilocycles is chosen this will not occur. To ensure that no difficulties of this sort occur a several section band-pass filter may be incorporated in the filter amplifier which may have its cutwere midway between the limits of the bandpass filter employed.

The differential frequency converter 80 may be sold as a unit for attachment to any standard type of receiver. The control unit 40 may also be sold separately, in fact a number 0 control units might be installed in various parts of the house for exciting the same receiver.

I do not wish to limit myself to the detection methods, type of oscillating circuits, number of stages type ofoscillator, power supply or type of gain control except in so far as may be set forth in the appended claims and required by the prior art.

I claim:

1. A radio receiving apparatus comprising an antenna system, a band-pass amplifier having an input circuit designed to pass a predetermined band of frequencies and associated with the antenna system, an intermediate frequency amplifier, a detector connected between the band-pass amplifier and said intermediate frequency amplifier, a filter transformer connected to select the frequency of the signals transmitted to the intermediate frequency amplifier, means for detecting the signal from the intermediate frequency amplifier, and audio frequency amplifying means connected to the output of the detecting means and a remote control unit'having an oscillator generating frequencies differing from the incoming signal frequencies by an amount numerically equal to that of the intermediate frequency amplifier and having a radiating loop loosely coupled to the input of the band-pass amplifier.

2. The combination of non-selective means for collecting broadcast signals of various frequencies, independently portable means for producing any desired frequency of control oscillations within a predetermined band of frequencies, means for varying the amplitude and frequency of the control oscillations, means for radiating the control oscillations, non-selective means for receiving and amplifying the collected signals and the control oscillation, means for mixing and detecting the amplified broadcast signal energy and the radiated control energy with the production of a certain super-audible frequency outside of the band-pass range, means for amplifying the resultant superaudible frequency, and means for redetecting said latter amplified energy, the frequency of control oscillations differing from the incoming broadcast signal frequencies by an amount numerically equal to the response frequency of the super-audible frequency amplifier.

3. A radio receiver having in combination a control oscillator, means for radiation of output of said control oscillator, means for the simultaneous collection of signals throughout a broad band of frequencies and of control oscillations, means for amplification of both signals and control oscillations with substantial uniformity regardless of frequency, means for detecting said signals and said control oscillations so as to produce a series of signals of frequencies differing from the frequencies of the control oscillations and the signals, means for selecting a predetermined dilfering frequency, means for adjusting the control oscillations so as to transfer the modulations of the desired signal to said predetermined differing frequency, means for the amplification and demodulation of said predetermined differing frequency and means for the amplification of the demodulations, said control oscillator being separateand located at a short distance from the remainder of the receiver.

4. Means for controlling a broadcast receiver from a distance comprising, a differential frequency converter adapted to be directly connected to the receiver and a separate remote control oscillato' unit, said converter consisting of an untuned amplifier for receiving all available signals within the frequency range of said broadcast receiver, and also receiving and amplifying the oscillations from the control unit, means for detecting said oscillations and said signals to produce signals of frequencies equal to the difference between the frequencies of the control oscillations and the signals, said detecting means having its output adapted for connection to the broadcast receiver, said control oscillator unit having means for varying the frequency of the produced oscillation in order to adjust the desired signal to the frequency to which the broadcast receiver is tuned.

5. The method of selective radio reception controlled from a distance such as within the limits of an ordinary apartment, which comprises, collecting all available signals in the range of the receiver within a predetermined band of frequencies covering a plurality of signal channels, producing oscillations of a control frequency and radiating the same a short distance, collecting said oscillations, amplifying said oscillations and said signals, detecting said oscillations and said signals so as to produce signals of frequencies equal to the differences of frequency between said signals and said control oscillations, selecting one of said produced frequencies and re-amplifying, demodulating and further amplifying it.

6. The method of household selective radio reception controlled froma distance which comprises, collecting all available signals in the range of the receiver within a pre-. determined band of frequencies covering a plurality of signal channels, producing oscillations of a control frequency and raaiating the same a short distance, collecting said oscillations, amplifying said oscillations and said signals, detecting said oscillations and said signals so as to produce signals of frequencies equal to the differences of frequency between said signals and said control oscillations, adjusting the frequency of said control oscillations until the desired one of said pro duced frequencies has a predetermined value, further amplifying said desired frequency and demodulating it. y

7. A single control household radio re ceiver comprising pick-up means for receiving radio frequency oscillations, untuned means for amplifying oscillations, a portable control unit remote from said pick-up and amplifying means and including means for producing control oscillations and single means for adjusting the frequency thereof, detector means connected to said untuned amplifying means for producing heterodyne frequencies from the interaction of such control oscillations and received broadcast signal oscillations, a filter tuned to a predetermined frequency equivalent to one of the detected heterodyne frequencies, amplifying means acting upon said heterodyne frequency after its detection and filtration, means for demodulating the amplified signalenergytoproduce audible frequency impulses and meansfor converting the same into sound, the control unit being movable independently of the other elements of the receiver.

BOWDEN WASHINGTON. 

